Bonded refractory ceramic and metal article

ABSTRACT

A method is disclosed for mechanically bonding a metal component to a ceramic material, comprising providing a metal component comprising an anchor material attached to at least a first portion of one surface of the metal component; providing a ceramic material having a first surface and a second surface, wherein the ceramic material defines at least one conduit extending from the first surface to the second surface, wherein the at least one conduit has a first open end defined by the first surface, a second open end defined by the second surface, a continuous sidewall and a cross sectional area; positioning the ceramic material such that at least a portion of the at least one conduit is in overlying registration with at least a portion of the anchor material; and applying a bonding agent into at least a portion of the at least one conduit.

CLAIMING BENEFIT OF PRIOR FILED U.S. APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/080,213, filed Apr. 1, 2008, now pending, which claims the benefit ofU.S. Provisional Application Ser. No. 61/004,648, filed on Nov. 29,2007. The content of these documents and the entire disclosure ofpublications, patents, and patent documents mentioned herein areincorporated by reference.

BACKGROUND FIELD

The present invention relates to refractory ceramics and specifically,to refractory ceramics for use in glass forming and/or delivery systems.

TECHNICAL BACKGROUND

The fusion process is one of the basic techniques used to produce sheetglass and can produce sheet glass having surfaces with superior flatnessand smoothness relative to sheet glass produced by alternativeprocesses, such as for example, the float and slot drawn processes. As aresult, the fusion process has found advantageous use in the productionof the glass substrates used in the manufacture of light emittingdisplays, such as liquid crystal displays (LCDs).

The fusion process, specifically, the overflow downdraw fusion process,includes a glass supply pipe which provides molten glass to a collectiontrough formed in a refractory body known as an isopipe. During theoverflow downdraw fusion process, molten glass passes from the supplypipe to the trough and then overflows the top of the trough on bothsides, thus forming two sheets of glass that flow downward and theninward along the outer surfaces of the isopipe.

Surfaces of a glass forming and/or delivery system that are in contactwith molten glass are typically comprised of a precious metal, such asplatinum. The stability of the glass supply pipe and other componentscan be dependent upon the materials and techniques of construction. Whensubjected to operating temperatures of 1,000° C. or more, conventionalmaterials can sag, creep, and/or deform, resulting in system and/orcomponent failure.

There is a need to address the aforementioned problems and othershortcomings associated with glass forming and/or delivery systems andthe traditional approaches for producing components for glass formingand/or delivery systems. These needs and other needs are satisfied bythe methods and articles of the present invention.

SUMMARY

The present invention relates to refractory ceramics and specifically,to refractory ceramics for use in glass forming and/or delivery systems.

In a first aspect, the present invention provides a method formechanically bonding a metal component to a ceramic material, comprisingproviding a metal component comprising an anchor material attached to atleast a first portion of one surface of the metal component; providing aceramic material having a first surface and a second surface, whereinthe ceramic material defines at least one conduit extending from thefirst surface to the second surface, wherein the at least one conduithas a first open end defined by the first surface, a second open enddefined by the second surface, a continuous sidewall and a crosssectional area; positioning the ceramic material such that at least aportion of the at least one conduit is in overlying registration with atleast a portion of the anchor material; and applying a bonding agentinto at least a portion of the at least one conduit.

In a second aspect, the present invention provides an article producedby the method described above.

In a third aspect, the present invention provides an article comprisinga metal component; an anchor material attached to at least a portion ofthe metal component; and a ceramic material having a first surface and asecond surface, wherein the first and second surfaces define at leastone conduit extending from the first surface to the second surface,wherein the at least one conduit has a continuous sidewall and a crosssectional area, the ceramic material being positioned on at least aportion of an exterior surface of the metal component and in overlyingregistration with at least a portion of the anchor material; and whereinat least a portion of the at least one conduit comprises a bondingagent, and wherein at least a portion of the anchor material issubstantially embedded in at least a portion of the bonding agent.

Additional aspects and advantages of the invention will be set forth, inpart, in the detailed description, figures, and any claims which follow,and in part will be derived from the detailed description or can belearned by practice of the invention. The advantages described belowwill be realized and attained by means of the elements and combinationsparticularly pointed out in the appended claims. It is to be understoodthat both the foregoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the invention as disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate certain aspects of the presentinvention and together with the description, serve to explain, withoutlimitation, the principles of the invention. Like numbers represent thesame elements throughout the figures.

FIG. 1 is a schematic view of a disassembled holey clam shell and metalcomponent welded with mesh patches, in accordance with various aspectsof the present invention.

FIG. 2 is a schematic view of an assembled holey clam shell inaccordance with various aspects of the present invention.

FIG. 3 is a schematic illustrating a top view of a holey clam shellcomponent and a plurality of casting holes, through which mesh patchesand a thermocouple welding pad are visible, in accordance with variousaspects of the present invention.

FIG. 4 is a cross section view of an individual casting hole,illustrating a rivet shaped ceramic castable mechanically bonding themetal component and the clam shell components together, in accordancewith various aspects of the present invention.

FIG. 5 is an exploded schematic of an alternate design, wherein two flatholey plates are each positioned on opposing sides of the metalcomponent, in accordance with various aspects of the present invention.

DETAILED DESCRIPTION

The present invention can be understood more readily by reference to thefollowing detailed description, drawings, examples, and claims, andtheir previous and following description. However, before the presentcompositions, articles, devices, and methods are disclosed anddescribed, it is to be understood that this invention is not limited tothe specific compositions, articles, devices, and methods disclosedunless otherwise specified, as such can, of course, vary. It is also tobe understood that the terminology used herein is for the purpose ofdescribing particular aspects only and is not intended to be limiting.

The following description of the invention is provided as an enablingteaching of the invention in its currently known embodiments. To thisend, those skilled in the relevant art will recognize and appreciatethat many changes can be made to the various aspects of the inventiondescribed herein, while still obtaining the beneficial results of thepresent invention. It will also be apparent that some of the desiredbenefits of the present invention can be obtained by selecting some ofthe features of the present invention without utilizing other features.Accordingly, those who work in the art will recognize that manymodifications and adaptations to the present invention are possible andcan even be desirable in certain circumstances and are a part of thepresent invention. Thus, the following description is provided asillustrative of the principles of the present invention and not inlimitation thereof.

Disclosed are materials, compounds, compositions, and components thatcan be used for, can be used in conjunction with, can be used inpreparation for, or are products of the disclosed method andcompositions. These and other materials are disclosed herein, and it isunderstood that when combinations, subsets, interactions, groups, etc.of these materials are disclosed that while specific reference of eachvarious individual and collective combinations and permutation of thesecompounds may not be explicitly disclosed, each is specificallycontemplated and described herein. Thus, if a class of substituents A,B, and C are disclosed as well as a class of substituents D, E, and Fand an example of a combination embodiment, A-D is disclosed, then evenif each is not individually recited, each is individually andcollectively contemplated. Thus, in this example, each of thecombinations A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are specificallycontemplated and should be considered disclosed from disclosure of A, B,and C; D, E, and F; and the example combination A-D. Likewise, anysubset or combination of these is also specifically contemplated anddisclosed. Thus, for example, the sub-group of A-E, B-F, and C-E arespecifically contemplated and should be considered disclosed fromdisclosure of A, B, and C; D, E, and F; and the example combination A-D.This concept applies to all aspects of this disclosure including, butnot limited to components of the compositions and steps in methods ofmaking and using the disclosed compositions. Thus, if there are avariety of additional steps that can be performed it is understood thateach of these additional steps can be performed with any specificembodiment or combination of embodiments of the disclosed methods, andthat each such combination is specifically contemplated and should beconsidered disclosed.

In this specification and in the claims which follow, reference will bemade to a number of terms which shall be defined to have the followingmeanings:

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to a “component” includes aspects having two or moresuch components, unless the context clearly indicates otherwise.

“Optional” or “optionally” means that the subsequently described eventor circumstance can or cannot occur, and that the description includesinstances where the event or circumstance occurs and instances where itdoes not. For example, the phrase “optionally substituted component”means that the component can or can not be substituted and that thedescription includes both unsubstituted and substituted aspects of theinvention.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

As used herein, a “wt. %” or “weight percent” or “percent by weight” ofa component, unless specifically stated to the contrary, refers to theratio of the weight of the component to the total weight of thecomposition in which the component is included, expressed as apercentage.

As briefly introduced above and with reference to the figures, thepresent invention provides a method for mechanically bonding a metalcomponent and a ceramic material, such as, for example, in a deliverypipe of a glass forming system. Among other aspects described in detailbelow and with reference to the figures, the inventive method comprisesthe use of a metal component 20, a ceramic material 50, and an anchormaterial, such as, for example, a metal mesh 34 or a plurality of metalparticles, to provide a mechanically strong bond between the metalcomponent 20 and the ceramic material 50.

While the methods of the present invention are not intended to belimited to a particular application, they can be used to reduce and/oreliminate sag of components in a glass forming and/or delivery system.Conventional materials used in a glass forming and/or delivery systemcan sag substantially during use because the mechanical strength atoperating temperatures is typically not sufficient to support the weightof the components themselves. The present invention provides methods toimprove the strength and durability of glass forming and/or deliverycomponents by employing anchor materials to help bond the ceramicmaterial to a metal component.

The present invention provides a novel approach to mechanically bond aceramic material with a metal. The invention provides a method forattaching an anchor material to a metal component, and then attaching aceramic material positioned on or around the metal component. Theceramic material can be attached to the metal component by placing abonding agent into one or more holes or conduits in the ceramicmaterial, wherein at least a portion of the bonding agent becomesmechanically bound to the anchor material on the metal component. Theceramic material can provide support to a metal component, therebyextending the useful life of the metal component and allowing the use ofa thinner metal component. In applications, such as glass formingsystems, where the metal component comprises a precious metal, use of athinner metal component can result in significant cost savings.

Ceramic Material

The ceramic material of the present invention can be any ceramicmaterial suitable for bonding to a metal component. The ceramic materialcan comprise a refractory oxide, such as, for example, ZrO₂, SiO₂, CaO,MgO, Al₂O₃, other refractory oxides, and/or mixtures thereof. Theceramic material can comprise an individual or multiple ceramicmaterials of varying compositions, particle sizes, and phases. Theceramic material can also comprise additives and/or sintering aids. Inone aspect, the ceramic material is compatible with conventional glassforming and/or delivery systems. In various aspects, the ceramicmaterial is capable of enduring temperatures typical of those in a glassforming and/or delivery system, for example, up to about 1,400, 1,450,1,500, 1,600, 1,650, or 1,700° C. or more. Ceramic materials arecommercially available and one of skill in the art could readily selectan appropriate ceramic material for use in a particular article and/orapplication. In one aspect, the ceramic material comprises an aluminaand/or zirconia material such as a high density, high purity alumina orzirconia available from Emhart Glass Manufacturing, Inc., Enfield,Conn., USA.

The ceramic material of the present invention can comprise one ormultiple pieces of the same or different individual ceramic materials.If multiple pieces are used, each individual pieces can be arrangedadjacent to another piece or in partial or complete overlyingregistration with another piece to form, for example, a mutli-layeredshell design.

In one aspect, the ceramic material has a material strength sufficientto resist deformation and/or sag at operating temperatures of theintended application. For example, a ceramic material used in a glassdelivery system should have a strength suitable to withstandtemperatures of about 1,400° C. or more without creep or sag.

The ceramic material can be provided in any form and/or shape suitablefor the intended use. In one aspect, a ceramic material is a sheet good,such as a flat plate. One or more such plates can be attached to one ormore surfaces of the metal component to provide, for example, structuralsupport. In one aspect, a single plate comprising a ceramic material ispositioned and attached to one surface of the metal component. Inanother aspect, two or more plates are positioned and attached tovarious surfaces of the metal component. It is not necessary that anytwo or more pieces of a ceramic material, such as a plate, have the samegeometry and/or composition, and aspects having both the same andvarying geometries and compositions are intended to be included as partof the invention. In a specific example, the metal component is aflexible tube and two ceramic plates are positioned and attached toopposing exterior surfaces of the flexible metal tube.

In another aspect, the ceramic material is one or more pieces of aceramic material formed into a predetermined shape, such that, forexample, the inner dimensions of the one or more pieces of ceramicmaterial match the profile of the outer dimensions of a metal componentto which they are to be attached. In a specific aspect, the ceramicmaterial comprises one or more pieces that form a clam shell around aflexible metal tube, as illustrated in FIGS. 1, 2, 3, and 5. In such aspecific aspect, each individual piece of a ceramic material can formthe top or bottom half of clam shell design. In such an aspect, eachindividual piece can be of varying length, for example, from about 6inches to about 36 inches in length. In one specific aspect, eachindividual piece is about 12 inches long.

The thickness of a ceramic material can be any such thickness suitablefor the intended application and can vary depending on factors, such as,for example, the operating temperatures to which the material will beexposed, creep strength, and the shape and geometric design of thematerial. In various aspects, the thickness of a ceramic material canrange from about 0.25 inches to about 4 inches, for example, about 0.25,0.35, 0.4, 0.5, 0.55, 0.6, 0.75, 0.8, 0.9, 0.95, 1, 1.25, 1.5, 2, 2.5,3, 3.5, or 4 inches. In a specific aspect, the thickness of a ceramicmaterial is about 0.5 inches. In other aspects, the thickness of aceramic material can be less than 0.25 inches or greater than about 4inches, and the present invention is not intended to be limited to anyparticular thickness.

The ceramic material 50 of the present invention, or any individualpiece thereof, can have one or more holes 52 extending from a firstsurface to a second surface thereof. Such holes can be described asconduits 52 defined by the ceramic material, each one or more conduithaving a first open end defined by the first surface of the ceramicmaterial, and a second open end defined by the second surface of theceramic material. Each of the one or more conduits has a continuoussidewall and a cross sectional area. Any two or more conduits, ifpresent, can have the same of differing sizes, shapes, profiles, and/orcross sectional areas.

In one aspect, a given piece of a ceramic material can be provided as asolid planar material without any such holes or conduits, or can beprovided wherein one or more such holes or conduits were pre-formed(FIG. 5), such as, for example, during casting or shaping of the ceramicmaterial. The holes or conduits can be positioned at pre-determinedlocations, such that at least a portion of a conduit can align with atleast a portion of an anchor material attached to a metal component 20to which the ceramic material is to be secured. If a ceramic material isprovided without conduits or with insufficient conduits to securelyattach to a metal component, one or more conduits can be created by, forexample, drilling a hole extending from the first surface to the secondsurface of the ceramic material.

The size and profile of any one or more conduits in a ceramic materialcan be the same or different from any other conduits. In one aspect, allof a plurality of conduits in a ceramic material are the same orsubstantially the same size and have the same or substantially the samesidewall profile. In another aspect, two or more conduits have differentsizes and/or different sidewall profiles. In various aspects, thediameter of any one or more conduits can be from about 0.75 inches toabout 1 inch, for example, about 0.75, 0.8, 0.85, 0.9, 0.95, or 1 inch.In other aspects, the diameter of any one or more conduits can be lessthan about 0.75 inches or greater than about 1 inch and the presentinvention is not intended to be limited to a particular diameter.

The sidewall profile of any one or more conduits can any suitable designsuch that when the ceramic material is aligned with the metal componentand an anchor material attached thereto, a bonding agent can be appliedin at least a portion of the conduit, flow through and/or around atleast a portion of the anchor material, and when cured and/orsolidified, provide a mechanical bond attaching the ceramic material tothe metal component. In various aspects, the sidewall profile of any oneor more conduits can be straight, curved, angled, or stepped. In oneaspect, the sidewall profile of any one or more conduits is straight. Inanother aspect, the sidewall profile of the conduit is chamfered. Inanother aspect, the sidewall profile of the conduit is dumbbell shaped.

In yet another aspect, the sidewall profile of any one or more conduitsis stepped such that the cross sectional area of the conduit at eitherthe first surface and/or the second surface is greater than the crosssectional area at other points of the conduit, as illustrated in FIG. 4.In a specific aspect, the cross sectional area of a conduit at both thefirst surface and the second surface is greater than that in the middleof the conduit. Such a sidewall profile can be obtained by, for example,drilling a counterbore 54 at either the first surface and/or the secondsurface, aligned with the axis of the conduit and having a largerdiameter than the conduit.

It is preferred that the sidewall profile of any one or more conduits bedesigned so as to form a rivet shaped body of bonding agent that issecured in place once the bonding agent is cured and/or fired. Such aninterlocking connection can result in a tighter fit between the metalcomponent and ceramic component.

Metal Component

The metal component 20 of the present invention can be any componentsuitable for mechanically bonding to a ceramic material. While theaspects described herein are related to a glass forming and/or deliverysystem, the present invention can be useful in any application where ametal component can be mechanically bonded to a ceramic material and thepresent invention is not intended to be limited to glass forming and/ordelivery systems. The metal component, in one aspect, is a metalcomponent that will deform under exposure to high temperatures, such asthose typical in a glass forming system. In one aspect, the metalcomponent is a portion of a glass forming system. In a specific aspect,the metal component is a metal portion of a glass delivery pipe. Inanother aspect, the metal component is a component, such as a sheet,that can be fabricated into a portion of a glass forming and/or deliverysystem. The specific dimensions and/or geometry of a metal component canvary depending on the intended application. In one aspect, a metalcomponent can be from about 0.010 inches thick to about 0.125 inchesthick, or greater, for example, about 0.01, 0.015, 0.02, 0.025, 0.03,0.035, 0.04, 0.05, 0.06, 0.08, 0.9, 0.1, or 0.125 inches thick. In onespecific aspect, the metal component can be about 0.040 inches thick. Inanother aspect, the metal component can be about 0.010 inches thick. Inother various aspects, the metal component can be thinner than 0.010inches or thicker than 0.125 inches thick and the present invention isnot intended to be limited to a particular thickness. It should beunderstood that the thickness of one or more metal components can varyand that the thickness of any individual metal component can bedifferent at various portions of the metal component.

The particular form of the metal component can be any such form suitablefor the intended application, such as, for example, a tube or sheet. Inone aspect, the metal component is a tube. In a specific aspect, themetal component is a tube formed from a sheet of a metal as describedherein. Such a tube can be prepared by seam welding the edges of a metalsheet to form a tube. The specific geometry and/or shape of any crosssection of the tube can vary and the present invention is not intendedto be limited to any particular geometry. In one aspect, the tube isflexible and can move and/or change shape as the volume of one or morefluids passing therein change.

The metal component of the present invention can comprise any metalsuitable for use in the intended application, such as, for example, aglass forming system. In various aspects, the metal component cancomprise at least one noble metal and/or noble metal alloy, at least oneplatinum group metal and/or platinum group metal alloy, or a combinationthereof. In one aspect, the metal component comprises a noble metal,such as gold, silver, tantalum, platinum, palladium, or rhodium. Inanother aspect, the metal component comprises a platinum group metal,such as, ruthenium, rhodium, platinum, palladium, osmium, or iridium. Inanother aspect, the metal component can comprise at least one refractorymetal, such as, for example, tungsten, molybdenum, niobium, tantalum,rhenium, and alloys thereof. In various specific aspects, the metalcomponent comprises platinum and/or a platinum/rhodium alloy, such as a90/10 wt. % or 80/20 wt. % platinum/rhodium alloy. Metal components andmaterials for fabrication of metal components are commercially availableand one of skill in the art could readily select an appropriate metalcomponent.

Anchor Material

The anchor material of the present invention can be attached to at leasta portion of the metal component and can provide a surface that can forma mechanical bond with at least a portion of a bonding agent. The anchormaterial of the present invention can be any material suitable for usein a metal/ceramic bonded application and that is capable of attachingto a metal component. The anchor material can comprise any geometrycapable of attaching to a metal component and forming a mechanical bondwith a bonding agent attached thereto. In one aspect, the anchormaterial is embedded and/or interlocked with at least a portion of thebonding agent 60. The anchor material can comprise, for example, a metalmesh 34, a plurality of metal particles, a sheet metal structure, or acombination thereof.

In one aspect, the anchor material is a mesh, such as a metal mesh. Ametal mesh anchor material can have multiple openings through which abonding agent can flow. The bonding agent can, in one aspect, fill atleast a portion of the openings and solidify, forming a mechanical bondbetween the metal component and the solidified bonding agent. A metalmesh anchor material can comprise any metal mesh capable of attaching tothe metal component and occluding at least a portion of a bonding agent.In various aspects, the metal mesh can have a mesh size of, for example,from about 3 mesh to about 80 mesh, for example, about 3, 4, 5, 8, 10,12, 14, 18, 20, 22, 24, 28, 30, 36, 40, 44, 48, 50, 52, 56, 58, 60, 62,64, 68, 70, 72, 74, 76, 78, or 80 mesh; from about 10 to about 40 mesh,for example, about 10, 12, 14, 18, 20, 22, 24 28, 30, 32, 34, 36, 38, or40 mesh; or from about 10 to about 25 mesh, for example, 10, 12, 14, 18,20, 22, 24, or 25 mesh. As used herein, the term “mesh size” is intendedto refer to the number of openings per linear inch of a material. In oneaspect, the metal mesh is a 20 mesh screen. In another aspect, the metalmesh is a 10 mesh screen. In various other aspects, the metal mesh canhave a mesh size of less than 3 or greater than 80, and the presentinvention is not intended to be limited to a specific mesh size,provided that the metal mesh can allow a bonding agent to flow throughand/or fill at least a portion of the mesh openings, solidify, and forma mechanical bond. In one aspect, the anchor material is capable ofbeing embedded or substantially embedded in at least a portion of abonding agent.

In various aspects, a metal mesh can comprise a wire having a nominaldiameter of, for example, from about 0.003 inches to about 0.060 inches,for example, about 0.003, 0.006, 0.009, 0.012, 0.015, 0.018, 0.020,0.025, 0.030, 0.036, 0.040, 0.044, 0.050, 0.058, or 0.060 inches; orfrom about 0.005 inches to about 0.020 inches, for example, about 0.005,0.008, 0.010, 0.012, 0.018, or 0.020 inches. In one aspect, the metalmesh comprises a wire having a nominal diameter of 0.008 inches. Inanother aspect, the metal mesh comprises a wire having a nominaldiameter of 0.010 inches. In various other aspects, the metal mesh cancomprise a wire having a nominal diameter of less than 0.003 inches orgreater than 0.020 inches, and the present invention is not intended tobe limited to a specific wire diameter. A metal mesh can be, forexample, woven, knitted, or other physical forms and the presentinvention is not limited to a particular form of metal mesh. In oneaspect, the metal mesh is woven. The size of, for example, a metal meshcan vary depending upon the size and dimensions of the desired articleand the properties (e.g., rheological properties) of a bonding agent,provided that the metal mesh can allow a bonding agent to flow throughand/or fill at least a portion of the mesh openings, solidify, and forma mechanical bond. In one aspect, a metal mesh is capable ofinterlocking or embedding at least a portion of the bonding agentapplied thereto. In another aspect, a metal mesh having a small meshsize is utilized when a fluid bonding agent having a viscositysufficiently low to allow at least a portion of the bonding agent toflow through and/or fill at least a portion of the mesh openings is tobe applied. In another aspect, a metal mesh having a large mesh size isutilized when a more viscous bonding agent is to be applied. The meshsize and wire diameter of a metal mesh can be selected to withstand aparticular stress, for example, under operating conditions.

The anchor material of the present invention can comprise metalparticles that can be attached to a metal component. The anchor materialcan comprise a plurality of metal particles dispersed on at least aportion of one surface of a metal component. The metal particles of ananchor material, if the anchor material comprises metal particles, canhave regular, irregular and/or varying shapes. It is not necessary thatthe metal particles have a specific shape or that all metal particleshave the same shape. It is preferred that at least a portion of theplurality of metal particles, if present, have a shape capable ofmechanically bonding a bonding agent applied thereto. In one aspect, theplurality of metal particles are attached and positioned such that abonding agent can flow around at least a portion of the plurality ofmetal particles and solidify, forming a mechanical bond. In anotheraspect, a plurality of metal particles can interlock or occlude abonding agent applied thereto. In various aspect, the metal particles ofan anchor material can have a diameter of, for example, from about 0.003inches to about 0.060 inches, for example, about 0.003, 0.006, 0.009,0.012, 0.015, 0.018, 0.020, 0.024, 0.030, 0.036, 0.040, 0.048, 0.050,0.052, or 0.060 inches; or from about 0.008 to about 0.020 inches, forexample, about 0.008, 0.012, 0.014, 0.016, 0.018, or 0.020 inches. Inone aspect, the metal particles have a diameter of about 0.016 inches.In another aspect, the metal particles have a diameter of about 0.020inches. In various other aspects, the metal particles can have adiameter smaller than 0.003 inches or greater than 0.020 inches. As usedherein, the term “diameter” refers to a median diameter of, for example,a metal particle. It is understood that the size and shape of metalparticles can vary and are typically distributional properties. In adistribution of, for example, particle sizes, the endpoints of thedistribution range can be above, at, or below the ranges describedabove. Thus, in one aspect, the metal particles have a median diameterof about 0.020 inches and can range from about 0.015 inches to about0.025 inches.

The anchor material of the present invention can comprise a sheet metalstructure. A sheet metal structure can comprise, for example, acorrugated piece of metal or a formed piece of metal that can beattached to a metal component and can accept and interlock a bondingagent. In one aspect, a sheet metal structure is designed and positionedsuch that a bonding agent can flow through, around, and/or over at leasta portion thereof and solidify, forming a mechanical bond.

The anchor material of the present invention can comprise any metalsuitable for use in the intended application, such as, for example, aglass forming system. In various aspects, the anchor material cancomprise at least one noble metal and/or noble metal alloy, at least oneplatinum group metal and/or platinum group metal alloy, at least onerefractory metal and/or refractory metal alloy, or a combinationthereof. In one aspect, the anchor material comprises a noble metal,such as gold, silver, tantalum, platinum, palladium, or rhodium. Inanother aspect, the anchor material comprises a platinum group metal,such as, ruthenium, rhodium, platinum, palladium, osmium, or iridium. Inanother aspect, the anchor material comprises a refractory metal, suchas tungsten, molybdenum, niobium, tantalum, or rhenium. In variousaspects, the anchor material comprises platinum and/or aplatinum/rhodium alloy. In a specific aspect, the anchor material isplatinum. In another specific aspect, the anchor material is aplatinum/rhodium (80/20) alloy. In yet another specific aspect, theanchor material is a platinum/rhodium (90/10) alloy.

The anchor material can comprise an individual or multiple metals.Further, if the anchor material comprises multiple individual pieces,such as for example, a plurality of metal particles, one or more piecesof metal mesh, or a combination thereof, each individual piece cancomprise either the same or differing compositions. The size and/orshape of any one or more pieces of anchor material, such as, forexample, metal mesh, can vary and can be the same or different fromother pieces of anchor material. In various aspects, an anchor materialcan be a square, disc, or strip of metal mesh material, and the presentinvention is not intended to be limited to any particular size and/orshape. The composition of a particular anchor material can be the sameor different from the composition of a metal component, provided thatthe anchor material is capable of being attached to the metal component.In a specific aspect, the anchor material comprises a metal mesh havinga 20 mesh screen size, a nominal wire diameter of about 0.008 inches,and is comprised of a platinum/rhodium (90/10) alloy. Anchor materials,such as, for example, platinum mesh and platinum particles, arecommercially available (e.g., Alfa Aesar, Ward Hill, Mass., USA) and oneof skill in the art could readily select an appropriate anchor material.

Attachment of Anchor Material

The metal component of the present invention can, in one aspect, beprovided with one or more anchor materials, as described herein,attached to at least one surface thereof. In another aspect, the metalcomponent can be provided with no anchor materials or insufficientanchor materials attached thereto, wherein one or more anchor materialscan be subsequently attached.

The anchor material of the present invention can be attached to at leasta portion of one surface of a metal component. It is not necessary thatan anchor material completely cover a metal component as the anchormaterial need only be present in a quantity and position sufficient toform a mechanical bond with at least a portion of a bonding agent. Inone aspect, the anchor material is attached to at least a portion of ametal component in a discontinuous fashion such that the anchor materialis not present in a continuous layer.

The metal component, such as, for example, a platinum alloy sheet, canoptionally be cleaned to remove oil and other surface contaminants andimpurities prior to attachment. Such a cleaning step can be performed,for example, using conventional detergents, surfactants, and/orsolvents.

The surface of a metal component can optionally be roughened prior toattachment using, for example, chemical and/or mechanical techniques. Inone aspect, the surface of a metal component to which an anchor materialis to be attached can be roughened by sand and/or bead blasting. Inanother aspect, the surface of a metal component to which an anchormaterial is to be attached can be roughened by a chemical etchingtechnique. It is not necessary that a cleaning or roughening step beperformed prior to attachment.

The anchor material of the present invention can be distributed on atleast a portion of one surface of the metal component. In one aspect,the anchor material can be positioned in a plurality of discretelocations on at least a portion of a surface of the metal component. Forexample, an anchor material comprising a metal mesh can be a singlepiece of metal mesh or multiple pieces of metal mesh positioned on asurface of the metal component. In one aspect, the one or more pieces ofan anchor material attached to the surface of a metal component can bepositioned at predetermined locations to correspond to the one or moreconduits of a ceramic material to which the metal component is to beattached. In one aspect, a piece of anchor material is positioned suchthat at least a portion of the anchor material will be in overlyingregistration with at least a portion of an open end of a conduit. Inanother aspect, a piece of anchor material is positioned such that theanchor material and the open end of a conduit in the ceramic material tobe attached thereto are in complete overlying registration.

In one aspect, a piece of metal mesh can be cut to a size and shape thatis similar to and/or matches the size and shape of a metal component. Inanother aspect, a piece of metal mesh can be smaller than a metalcomponent. An anchor material comprised of metal particles can bedistributed randomly, in a pattern, or in a uniform manner on a surfaceof the metal component. In one aspect, a metal particle anchor materialis uniformly distributed across the portion of the metal componentsurface to which a bonding agent is to be applied. In another aspect, ametal particle anchor material can be distributed in a predeterminedpattern to enhance bonding and thus, strength of a bonded article inparticular high-stress regions.

After contacting an anchor material to a portion of a metal component,the anchor material can be attached using any suitable technique. Invarious aspect, the anchor material can be attached using one or morewelding techniques, such as, for example, arc welding, resistancewelding, fusion welding, spot welding, seam welding, electron beamwelding, ultrasonic welding, laser welding, or a combination thereof. Ina specific aspect, at least a portion of the anchor material is spotwelded to the metal component at one or more locations so as to preventmovement of the anchor material during assembly. In one aspect, theanchor material can be attached to a metal component by heating themetal component and anchor material at a time and temperature sufficientto fuse at least a portion of the anchor material to the metalcomponent. It is not necessary that the anchor material completely fuseto the metal component so long as a sufficient quantity of anchormaterial is fused to allow bonding of a ceramic material. In variousaspects, the contacted anchor material and metal component can be heatedat a temperature of at least about 1,300° C., for example, 1,300, 1,400,1,500, 1,600, 1,650, 1,700° C. or greater, for a period sufficient toattach at least a portion of the anchor material to at least a portionof the metal component, such as, at least about 0.25 hours, for example,about 0.25, 0.5, 0.75, 1, 2, 4, 6, 8, 10, 12, 16, or 24 hours; for atleast about 2 hours, for example, about 2, 4, 6, 8, 10, 12, 16, or 24hours, or for at least about 5 hours, for example, about 5, 6, 7, 8, 9,10, 12, 14, 18, or 24 hours. The specific time and temperature ofheating can vary. A shorter heating time, such as, for example, about 20minutes, can be utilized if the temperature is sufficiently high toattach at least a portion of the anchor material to at least a portionof the metal component. In one aspect, the contacted anchor material andmetal component is heated at about 1,650° C. for a period of about 2hours. In another aspect, the contacted anchor material and metalcomponent are heated at about 1,700° C. for a period of about 20minutes. The anchor material and metal component can be heated at ahigher temperature and/or for a longer period of time, provided that theincreased heating does not adversely affect the materials and/or theirability to fuse and interlock a bonding agent. The anchor material andmetal component can be heated at a lower temperature and/or for ashorter period of time, provided that at least a portion of the anchormaterial can fuse to at least a portion of the metal component.

During heating, pressure, such as, for example, a compressive force, canoptionally be applied to the anchor material and the metal component toenhance and/or speed the attachment process. The pressure applied, ifany, can vary depending upon the specific materials and heatingconditions. In one aspect, a pressure of at least about 1 psi is appliedto the anchor material and metal component during heating. In anotheraspect, a pressure of at least about 10 psi is applied to the anchormaterial and metal component during heating.

Other techniques for attaching materials, such as, for example, weldingand/or adhesive techniques, can be utilized provided that materialsattached using such techniques are stable at temperatures to which themetal component will be exposed. One or more techniques can be used toattach an anchor material to a metal component. Metal fusing and weldingtechniques are known in the art and one of skill in the art couldreadily select an appropriate technique and conditions for attaching ananchor material to a metal component.

If a metal component is not originally provided in a form or shapesuitable for the intended application, it can optionally be formed intosuch a desired shape either prior to, simultaneous to, or subsequent tothe attachment process. In one aspect, a platinum sheet is provided andis formed into a pipe prior to the attachment process. In anotheraspect, a platinum sheet is provided and is formed into a pipe after theattachment process.

Bonding Agent

The bonding agent of the present invention can be any suitable agent forthe intended application that can form a mechanical and/or interlockingbond between an anchor material and a ceramic material. Such a bondingagent can flow through and/or around an anchor material, such as a metalmesh or metal particles, such that, when dried, fired, and/or cured, atleast a portion of the bonding agent is embedded or substantiallyembedded in at least a portion of the anchor material.

In one aspect, the bonding agent is a castable ceramic material, suchas, for example, ZrO₂, SiO₂, CaO, MgO, Al₂O₃, other refractory oxides,and/or mixtures thereof. As used herein, the term bonding agent canrefer to a material that is not solidified, such as, for example, aslurry or mixture of ceramic components, or to a dried, fired, and/orcured material that fills at least a portion of a conduit in the ceramicmaterial and is embedded or substantially embedded in at least a portionof an anchor material. In another aspect, the bonding agent comprisesthe same or substantially the same composition of the ceramic material.

The bonding agent can comprise an individual or multiple bonding agentsof varying compositions, particle sizes, and phases. The bonding agentcan also comprise additives and/or sintering aids. In one aspect, thebonding agent can comprise at least one additive to control and/oradjust the rheological properties, such as, for example, viscosity, ofthe bonding agent. In another aspect, the bonding agent is compatiblewith conventional glass forming and/or delivery systems. In variousaspects, the bonding agent is capable of enduring temperatures typicalof those in a glass forming and/or delivery system, for example, up toabout 1,400, 1,450, 1,500, 1,550, 1,600, 1,650, or 1,700° C. or more.Bonding agents are commercially available and one of skill in the artcould readily select an appropriate bonding agent for use in aparticular article and/or application.

Application of Bonding Agent

Prior to assembly of the one or more pieces of ceramic material and themetal component, the one or more pieces of ceramic material canoptionally be sealed with at least one of a paste cement, castableceramic, seal agent, such as a glass frit material. Such a sealing step,if performed, can improve the operational lifetime of a ceramic materialby preventing oxygen diffusion into the material. After assembly of theone or more pieces of ceramic material with the metal component, suchthat at least a portion of the at least one conduits is in overlyingregistration with at least a portion of an anchor material, asillustrated in FIGS. 2 and 3, the boding agent of the present inventioncan be applied in at least a portion of at least one conduit of theceramic material using any suitable technique. In one aspect, thebonding agent is applied from the exterior surface of the ceramicmaterial such that at least a portion thereof flows through, around,and/or over at least a portion of the anchor material located at theopposing end of the conduit. Depending on the physical properties, suchas rheology, the bonding agent can be applied at various times, such as,for example, prior to assembly of the ceramic material and the metalcomponent, provided that a sufficient quantity of the bonding agentremains in the conduit so as to provide the desired interlocking bondwith at least a portion of an anchor material positioned on the metalcomponent.

The application of bonding agent to one or more conduits in the ceramicmaterial can be performed simultaneously or sequentially. It is notnecessary that all conduits be filled with bonding agent nor thatbonding agent be applied in all conduits at the same time. Such a designcan provide greater flexibility during assembly than previous methods.

In one aspect, a castable ceramic bonding agent, such as, for example, azirconia, can be mixed with a binder and then be pasted into one or moreconduits. The viscosity of the bonding agent should be such that atleast a portion of the bonding agent will flow into and fill the meshopenings of a metal mesh anchor material attached to a metal component.In a preferred aspect, a quantity of bonding agent is applied sufficientto flow through or around at least a portion of an anchor material andto fill a conduit such that a rivet shaped plug of bonding agent isformed.

Any portion of applied bonding agent that extends beyond the conduit andthe exterior surface of the ceramic material can optionally be removedby, for example, scrubbing, scraping, and/or grinding, so that a theexterior surface of the ceramic material is substantially flat.

In another aspect, the bonding agent is applied such that at least aportion of the attached anchor material is embedded or substantiallyembedded in at least a portion of the bonding agent. It is not necessarythat an anchor material be completely embedded in a bonding agent,provided that one or more anchor materials are embedded to the extentnecessary to mechanically bond a portion of the ceramic material to atleast a portion of a metal component. In one aspect, at least one anchormaterial is completely embedded in a bonding agent. In another aspect,at least one anchor material is substantially embedded in a bondingagent, such that the anchor material interlocks with the bonding agent.In another aspect, a metal mesh anchor material has a least a portion ofthe mesh openings filled with the bonding agent. In yet another aspect,at least a portion of a plurality of metal particles are at leastpartially surrounded by at least a portion of the bonding agent.

The rheological properties of a bonding agent can be controlled and/oradjusted with additives such that at least a portion of the bondingagent can flow through, around, and/or over at least a portion of theanchor material. A bonding agent applied in such manner can be allowedto solidify or harden such that a mechanical bond is formed between theanchor material/metal component combination and the bonding agent.

After application, a bonding agent can be solidified. Suchsolidification can, in one aspect, comprise allowing the bonding agentto dry, harden, and/or cure without additional steps. In another aspect,solidification can comprise heating and/or firing the applied bondingagent. In one aspect, the applied bonding agent can have a green bodystrength sufficient for the intended application. In one aspect, thecast bonding agent can be dried for a period of from about 10 to about48 hours prior to firing.

EXAMPLES

To further illustrate the principles of the present invention, thefollowing examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how themethods and articles, devices claimed herein are made and evaluated.They are intended to be purely exemplary of the invention and are notintended to limit the scope of what the inventors regard as theirinvention. Efforts have been made to ensure accuracy with respect tonumbers (e.g., amounts, temperatures, etc.); however, some errors anddeviations should be accounted for. Unless indicated otherwise,temperature is ° C. or is at ambient temperature, and pressure is at ornear atmospheric. There are numerous variations and combinations ofprocess conditions that can be used to optimize product quality andperformance. Only reasonable and routine experimentation will berequired to optimize such process conditions.

Example 1 Attachment of Platinum Mesh to Platinum Plate (Prophetic)

In a first example, about 10 pieces of a platinum/rhodium (90/10 wt. %)alloy 20 mesh screen having a nominal wire diameter of 0.008 inches canbe attached to a platinum plate. The pieces of mesh can be cut intoapproximately 1 inch by 1 inch squares and positioned in discretelocations on top of the platinum plate. The mesh/plate combination canthen be spot welded to the plate.

Example 2 Attachment of Ceramic Plate (Prophetic)

In a second example, an alumina plate having about 10 holes can beprovided, where the holes are positioned in approximately the samepattern as the pieces of anchor material in Example 1. Each hole can beabout 0.75 inches in diameter and have a larger countersunk portion onboth surfaces of the alumina plate. The alumina plate can be placedadjacent to the platinum plate such that at least a portion of each ofthe holes in the alumina plate are aligned with the metal mesh attachedto the metal plate. Then, a castable alumina can be prepared with aviscosity such that the castable alumina can flow through the holes ofthe metal mesh. Each of the holes in the alumina plate can then befilled with the castable alumina. The castable alumina can then beallowed to dry.

What is claimed is:
 1. An article comprising: a metal component; ananchor material attached to at least a first portion of one surface ofthe metal component; a ceramic material having a first surface and asecond surface, wherein the ceramic material defines at least oneconduit extending from the first surface to the second surface, whereinthe at least one conduit has a first open end defined by the firstsurface, a second open end defined by the second surface, a continuoussidewall, and a cross sectional area; the ceramic material positionedwith respect to the metal component such that at least a portion of atleast one of the first open end and the second open end of the at leastone conduit is in overlying registration with at least a portion of theanchor material; and a castable ceramic bonding agent located within atleast a portion of the at least one conduit, wherein the castableceramic bonding agent is located at one or more of: (1) an opening in atleast a portion of the anchor material located at an opposing end of theat least one conduit; (2) around at least a portion of the anchormaterial located at the opposing end of the at least one conduit; and(3) over at least a portion of the anchor material located at theopposing end of the at least one conduit, and wherein the castableceramic bonding agent forms a mechanical bond between the metalcomponent and the ceramic material.
 2. The article of claim 1, whereinthe castable ceramic bonding agent forms the mechanical bond capable ofenduring temperatures above 1400° C.
 3. The article of claim 1, furthercomprising a plurality of anchor materials attached to the metalcomponent.
 4. The article of claim 1, wherein the ceramic materialdefines a plurality of conduits, wherein each conduit has a first openend defined by the first surface, a second open end defined by thesecond surface, a continuous sidewall, and a cross sectional area. 5.The article of claim 1, wherein at least a portion of the second surfaceof the ceramic material is in contact with at least a portion of the onesurface of the metal component.
 6. The article of claim 1, wherein thecross sectional area of the at least one conduit is larger at the firstsurface or the second surface than at any other point of the at leastone conduit.
 7. The article of claim 1, wherein the cross sectional areaof the at least one conduit is larger at both the first and secondsurfaces than at any other point of the at least one conduit.
 8. Thearticle of claim 1, wherein the continuous sidewall of the at least oneconduit has a stepped profile, and wherein the cross sectional area at acenter of the at least one conduit is smaller than the cross sectionalarea of at least one of the first surface and the second surface of theat least one conduit.
 9. The article of claim 1, wherein the anchormaterial comprises a metal mesh, and wherein the metal mesh has multipleopenings within which there is located at least a portion of thecastable ceramic bonding agent.
 10. The article of claim 1, wherein theanchor material comprises platinum, a platinum alloy, or a combinationthereof.
 11. The article of claim 1, wherein the anchor materialcomprises a plurality of metal particles, and wherein at least a portionof the castable ceramic bonding agent is located around at least aportion of the plurality of metal particles.
 12. The article of claim11, wherein the plurality of metal particles have at least one offollowing: (1) a regular shape; (2) an irregular shape; and (3) varyingshapes.
 13. The article of claim 1, wherein the anchor materialcomprises a sheet metal structure.
 14. The article of claim 13, whereinthe sheet metal structure is a corrugated piece of metal that acceptsand interlocks the castable ceramic bonding agent.
 15. The article ofclaim 13, wherein the sheet metal structure is a formed piece of metalthat accepts and interlocks the castable ceramic bonding agent.
 16. Thearticle of claim 1, wherein the metal component comprises at least onenoble metal and noble metal alloy thereof, at least one platinum groupmetal and platinum group metal alloy thereof, or a combination thereof.17. The article of claim 1, wherein the metal component comprisesplatinum, a platinum alloy, or a combination thereof.
 18. The article ofclaim 1, wherein the metal component comprises at least one of a noblemetal and a noble metal alloy thereof.
 19. An article comprising: ametal component; an anchor material attached to at least a portion ofthe metal component; a ceramic material having a first surface and asecond surface, wherein the first and second surfaces define at leastone conduit extending from the first surface to the second surface,wherein the at least one conduit has a continuous sidewall and a crosssectional area, the ceramic material being positioned on at least aportion of an exterior surface of the metal component and in overlyingregistration with at least a portion of the anchor material; and,wherein at least a portion of the at least one conduit comprises abonding agent, and wherein at least a portion of the anchor material issubstantially embedded in at least a portion of the bonding agent. 20.The article of claim 19, wherein the bonding agent comprises arefractory oxide ceramic material.
 21. An article made by a methodcomprising: providing a metal component comprising an anchor materialattached to at least a first portion of one surface of the metalcomponent; providing a ceramic material having a first surface and asecond surface, wherein the ceramic material defines at least oneconduit extending from the first surface to the second surface, whereinthe at least one conduit has a first open end defined by the firstsurface, a second open end defined by the second surface, a continuoussidewall, and a cross sectional area; positioning the ceramic materialsuch that at least a portion of at least one of the first and/or secondopen ends of the at least one conduit is in overlying registration withat least a portion of the anchor material; and applying a bonding agentinto at least a portion of the at least one conduit.